In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it. Your job is to determine which sentence(s) from the passage can be used to search for further information needed to answer the question.
Q: Question: How long had the United Nations been in existence when Gross was appointed? Passage:On October 11, 1949, United States Secretary of State Dean Acheson appointed Gross as the United States' deputy delegate to the United Nations. Only two months later, the chief delegate, Warren Austin, took a leave of absence, and Gross took over as acting head of the U.S. delegation to the U.N. The major issue facing the United Nations at that time was the Soviet Union's proposal that, with the conclusion of the Chinese Civil War, the Communist People's Republic of China should replace the Republic of China on the United Nations Security Council. On January 13, 1950, the Soviet delegate, Jacov Malik, walked out of the Security Council in protest. Malik remained absent for several months, and as such the Soviet Union failed to exercise its veto power to block United Nations Security Council Resolution 82, which condemned North Korea at the beginning of the Korean War; on behalf of the U.S., Gross voted in favor of the resolution. In fall 1950, Warren Austin returned from his leave of absence, and Gross continued to serve as Austin's deputy until 1953.

A: 
On October 11, 1949, United States Secretary of State Dean Acheson appointed Gross as the United States' deputy delegate to the United Nations